Machine for driving curved selfretroverting nails



A July 2,1946. 2,403,222

MACHINE FOR DRIVING CURVED SELF-RETROVERTING NAILS J. N. M. HOWELLS s Sheets-Shet 1 Y Filed April '19} 1945 luvuTor x/omv NM vawsusv A TORNEY July 2, 1946. J. N. HOW4ELL$ 2,403,222 MACHINE'FOR DRIVING GURVED SELF-RETROVERTING NAILS Filed April 19, 1943 s- Shets-She et 2 INVENTOR JoH/v N M Hon 544s A TORNEY July 2, 1946. J. N. M. HOWELLS" 2 MACHINE FOR DRIVING GURVED SELF RETROVERTING NAILS Filed April 19, 1945 s s eets-sheet 5 .,4 INVENTOR E ATiORNEY Patented July 2, 1946 UNITED STATES PATENT OFFICE MAOHINEHFOR DRIVING CURVED SELF- RETROVERTING NAILS 24 Claims.

This invention relates to a machine for driving curved self-retroverting nails, the same being of the type disclosed in my co-pending application for Fastening devices and means for applying the same, Serial No. 440,342, filed April 24, 1942. In said application I have shown a tool for driving a curved, self-retroverting nail by successively applying to portions of the nail shank, as they pass beneath the point of application, a force. substantially normal to the surface of the material into which the nail is being driven. While such tool is quite simple in construction, it is particularly adaptable for manual operation, and, due to the many blows required by it to drive a nail home, does not lend itself to use in a high speed, self-powered device for driving nails of the character described.

It is,-therefore, an object of my invention to provide a machine which can drive home a nail of the character described with one blow or at the most two blows, the latter only being required when the nail extends arcuately close to 180.

Another object of my invention is to provide a machine which can drive home a nail of the: character described with one or more blows normal to the head and thus not applied normal to the surface of the material. into which the nail is being driven.

In my aforesaid co-pending application the.

self-clinching nail has been illustrated as having a plurality of notches in the shank. While this simplified the construction of the driving tool, it somewhat weakened the nail and the. shank had to be of a slightly greater diameter in the notched portions than would normally be required under given conditions. It is, therefore, a further object of the present invention to provide a machine or tool for driving a nail of the character described having a shank of uniform crosssection.

An additionalobject of my invention is to provide a self-powered machine for driving nails of the character described, which shall comprise relatively few and simple parts, and be ruggedin construction, efiicient, quick and durable in operation, and economical to manufacture and use.

Other objects of this invention will in part be obvious and in part hereinafter pointed out..

Theinvention accordingly consists in the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter described, and of which the scope of application will be indicated in the appended claims.

In the accompanying drawings, in which is shown one of the various possible embodiments of this invention,

Fig. 1 is a side View of-a curved self-retroverting nail adapted. to be driven by a machine embodying my invention;

Fig. 2 is a top plan view of said nail;

Fig. 3 is a sectional view of the nail shank taken substantially along the line 3-3 of Fig. 1;-

Fig. 4 is an auxiliary plan view of thenail head taken substantially along the line 4-4 of Fig. 1;

Fig. 5 is a top plan view of a nail driving machine embodying the invention with the nail magazine partly broken away;

Fig. 6 is a central longitudinal section taken substantiallyalong the line 66 of Fig. 5 and illustrating the various means for applying and controlling the application of power to the means for actuating nail driving elements;

Fig. '7 is a central longitudinal section through the means for actuating the nail driving elements and through the nail holding magazine;

Figs. 8 and 9 are enlarged sections taken substantially along the lines 8-8 and 9-9 of Fig. 7 and illustrating the gear trains forming part of the means for actuating the first acting and sec- 0nd acting nail driving elements respectively;

Fig. 10 is an enlarged sectional view taken substantially'along the line l0l0 of Fig. 7 and illustrating the first acting nail driving element and the means for actuating the same immedi ately prior to the initiation of an operative stroke;

Fig. 11 is a sectional view taken substantially along the line I l-ll of Fig. IO and showing a detail of the means for actuating the first acting nail driving element;

Fig, 12 is asectional view taken substantially along the line |2l2 of Fig. 7 and illustrating the means for actuating the second acting nail driving element while the same is at rest;

Fig. 13 is a. sectional View taken along the line I3-I3 of Fig. 12 and showing a detail of the means for actuating the second acting nail driv-,

ing element;

Fig. 14 is a View similar to Fig. 10 with the parts positioned at the. end of an operative stroke of the first acting nail driving element;

Fig. 15 is a sectional view taken substantially along the line l5l5 of Fig. 14;

Fig. 16 is a sectional view taken substantially along the line Iii-l6 of Fig. 7 after the comple-' tion of the stroke of the second acting nail driv,

ing element; and? Fig. 17 is a sectional" view taken substantially along the line i'|-l'l of Fig. 7 and illustrating details of the nail holding magazine and the means for feeding nails into driving position.

Referring now to'the drawings and moreparticularly to Figs. 1-4, I havethere shown a selfr'etroverting nail H! of the same general characteristics and attributes as that illustrated, described and claimed in my said co-pending application, The nail It includes a curved shank [2 which is tipped at one end by a driving point I4 and provided at the other end with a head l6. 1 The shank I2 is preformed to a shape such; that the direction of the driving point M has a In addition to the foregoing means, the ma-.

chine may include a means such as a magazine to house and feed a supply of curved nails, self- 7 contained power means to actuate the nail drivcomponent directly opposed to the direction of} travel of the nail head l6. As will later be apparent from the description of the machine for driving the nail, the most easily drivenforrn of' shank which has this relative disposition of pointf and head is a substantially circular segment.

Such segment may embrace an arc of from about 90 to about 180. Obviously the greater the arc the greater will be the self-retrove'rting effect which is obtained and the greater will be the difii- It will later be seen culty in driving the nail, that nails having shanks of an are greater than 90 but substantially less than 180 can be driven in a machine embodying my invention with but one blow, and that'nails embracing an arc of onlf'slightly less than 180 require two blows. However, the provision of a machine for driving bothsuch classes of self-retroverting nails is within the scope of the instant invention. N

The cross-sectional contour of the shank l2 may be circular, as illustrated in Fig. 3, or may assume any other desirable or conventional outline, as for example, oval, rectangular or triangular. Also, the nailmay be of uniform crosssectional contour as shown in Figs. 1 and 2, or gradually tapered from head to tip with an abrupt taper at the tip to' form a point, or it may be notched as illustrated in my said co-pending ape plicat'io'n or barbed'or roughened as is common in'the art, without affecting the basic construetion'or operation ofmy novel machine for driving thesame.

The head of the nail may be longer than the diameter of the shank in-one dimension, preferably though not necessarily the plane in which the-nailis curved, and no greater than said diameter at-right-angles to this plane. Alternatively, the head? may simply comprise an end of the shankand have no portion projecting laterally beyond the same. q

To drive the nail into material, the nail point should be applied to the surface of the material at right angles thereto. First the point and next the nail shank are then forced in. During insertion of the shank, the portion entering the material is usually disposed about normally to the surface of the material. As disclosed in my said 'co-pending' application, the nail can, be driven in this'manner by employing a tool which enables'striking' successive portions of the nail shank immediately prior to their entry into the" ing means, a frame and housing to unite the various parts of the mechanism or tool into a unitary whole, and a simple manually actuated ntrol means forsetting the machine into op- I eration, 7

Referring now to Figs. 5-17, I have there disclosed a machine I8 which embodies my-invention. Said machine may include a thick base 20 which serves as a bed on which the several elements of the machine are mounted, and a lighter casing '22 which cooperates with the bed 20 to form an enclosing housing for the'apparatus. The; casing and bed are provided with a lifting yoke 23 to facilitate carrying' and'positioning of the machine. The outlined the bed 20 and casing 22 is generally such as to conform relatively closely to the overall exterior contour of the several elements contained in the housing and which will not be described.

The source of power for the machine is derived from a high speed electric motor 24 (Fig. '6) which is bolted to the bed 20 and is supplied with current by lead wires 25 adapted to be detachably connected to any convenient electric power outlet. The motor shaft 26 is coupled to a fly-wheel 28 through a slip-drive 30 of standard construction, such as a pair of hardened steel discs 30a, 301), one of which discs Silb is slidably mounted axially of a shaft 30c and pressed by a spring Slidinto frictional surface contact with the other disc 30a. Bearing pedestals32, to either side of the fly-wheel support the fly-Wheel shaft 36 Said shaft is coupled to the input shaft of a gear reduction drive 38 whose output shaft turns a one-revolution clutch 40 of conventional design, comprising for example a pair of coaxial members 40a, 40?) provided with conical nestable clutch portions which are spaced apart when the clutch is disengaged. The driven clutch member 40b, which is spline connected to the shaft on which it is supported, is urged into engagement with the driving member Mia upon depression of a button, 32. Said button is mounted on a shaft 43 vertically reciprocable in the casing22 and is biased upwardly by a spring 44. "At the lower end of theshaft 43 there is attached a cam 45 which is disposed adjacent a rim of the driven clutch member 4019 and is adapted to urge said member into engagement with the driving mem ber. 40a when the button is pushed. ,The driven member 4% carries a longitudinally disposed leaf spring 400 in which an inwardly extending rearwardly tapered rib 40d is formed. Said rib is adaptedto lie in anannular groove dfie in the driving member 40a When the two member are engaged and serves to keep theclutch inengagement. The spring 460 extendsfor a substantial distance beyond the rib lad. 7 This extending portion is adapted to cooperate with a wedge-shaped stopping dog 40f-which is shiftable parallel to the axis of theshaft on which the member 40a is supportede. 98 W is i r ses sqb a.

sausage when the button is in its upper position; and

the dot z'aJhd-dash line position when the button 42 is "depressed. Whenit is desired -'to ren- =der the clutch efiectivejthe button 42 depressed thereby urging the member 48b into eng'a'ge'znent with the member 40a and moving the dog "4'0-f to ineffective position. The driven member "tab will then start to-re'volve, the two clutch 1 members 40d, '"40b being held together by the s" mg 400. When the button 42 is released, the dog '40) will spring back to stobpin (full line) irr'os'ition so that'a'fter the member 49b has made one revolution, the spring 400 will engage the nsane ride partially 'up its inclined surface. "I h will raise'the =rib 40d and allow a spring 40 to separate the two'clutch members. Frictional engagement between the spring and dog prevents movement ofthe driven member 4% until thebutton4 2is again depressed.

The one-revolution clutch 40 'turns a shaft on which are mounted two adjacently disposed mutilated gears '48, (Fi'gs. 7, 8. and 9). One of these gear meshes with a cogwheel "52'on'a drive shaft 54 journalled in a bearing post 56. The other mutilated ear 50 engages a second cogwheel 58 disposed coax'ially of the cogwheel 52 and supported on a sleeve 60 journalled on said drive shaft '54. The cog'wheels 52, 58 are keyed to the drive shaft and sleeve respectively. The forward end'of the drive shaft 54 is journalled in a standard 62. v V

A slotted driving crank 64 (Figs. '7 and 10) is secured to the drive shaft immediately adjacent said standard. The slot in said crank may be o'fise't from said drive shaft 54 and has slidably received therein a roller 66 which'is journalled on a post '58 projecting from a circularly seg- 'me'nta1 block 10 (Figs. 10 and 11) which slides in an arc'uate channel 12 formed in the wall of the cas'ing22 adjacent the nail magazine. This channel has a center of curvature substantially coincidentwith the center of curvature of nails 10 in the nail magazine M. As' will be seen in Figal-l, the mouth 14 of the channel is narrower than the-base thereof and the block 10 provided with a shoe 1'! which is slidably retained within the channel. To facilitate insertion of the shoe into said channel a portion 16 (Fig. 12) of the channel is cut away jso that the mouth thereof is of the full width of the channel base. As will soonbe seen, this portion is beyond the normal travel-of "said block. A portion of the block 10, which projects through the channel mouth, carries a hammer element 18 hereinafter referred to r This element is adapted to ride in a semi-circular driving slot 80 in the standard 62. The two ends of the slot are located adjacent the base 20 of the machine (as shown in Fig. 10), the slot being adapted to receive the shank I2 of a nail I0 'withthe head thereof disposed near one end of the slot and the tip thereof disposed at the other end of the slot. The base is aperture'd at B l to permit a reinforcing extension on the back of the-first hammer to lie flush with the base of 4' tottom or the drivi'ng slot"-'B0 w ile "the nail is terns dnveh. q r I Vlfihe'n {the hammer s is in starting iiositm the mutilated gear Me issa a a-ily di sposed rerat e 'tojth'e coewheel sz t at he j' mu tila'ted orsion just tenhmatea its -a.-v11t ereever and the "gear is ready t -start driving 'theeo'g' wheel. The mutilated-portion "of th gear esters. arcsueh that iip'on rotation hr theshart ts' therethrou'gh "thec'egwheertz will' tiirn the drive shaft '54j an angular distance sumeiehtfto move the first hammer through a driving stroke of;substantia1angular length, whichin the hitstrated embodiment of my invention is ap ro inately 120. 'rhe'hosition er the first hammer at the end or its driving stroke and er the drivihg means therefore (thecrank "s 4 andbIoc-k 1'0 'atsiich timeis Shawn by the run unes in 4. When the gear 48 rotates further the eogwhei "52 "will be disengaged thereby allowing theco'g' wheel 52, block "10, crank 54, and first hammer 18 to be'returnedhtotheir starting positions "by a. spring 84 tensioned between a fixed 1;' 01"-Iit "6n the machine 18' and an arm 86 secured to the drive shaft 54. I p

It Will be appreciated that when the hammer l8st'arts to drive the nail it 'a'pphesa forc'eliaving a large component pointed-opposite to 'thed-iifec; 'tion 'inwhic'h the tip of the nail is 'faeing. This com onent tends to distort the nail 's'ha"k "and liftthe nail away from the base-of the machine. In order to prevent the applied rorceffrhm thus interfering with driving of a "nail, I haveprovided means 'for supporting and guidinga' nail being-driven whereby the "force applied normal to the head ofthe nail is transmitted along the curved nail shank to the point thereof without distorting "the nail or moving the same in Ifa'ny but the desired manner and direction. Said means comprises an arcuate groove 88 in the'wall of the slot 80 facing the nail magazine. Said groove "is coaxial with the driving slot and is of such depth and contour that it will snugly "receive a lateral portion of a nail shank exposed by a nail head. The extent of such 'portionisdetermined by the amount the nail head is narrower than the nail sha'nk, as clearly "shown in Fig, 4. The angular positioniand configurationof th'e'nail head 1 Sand groove 88 may be considerably varied provided only that the head is not allowed to prevent the flanks of adjacent nail shanks from remaining in contact while a nail is being driven. If 'desired'or necessary, the variation may even be si1'ch as to provide a confining and guiding surface directly over a nail being driven. It will be understood, of course, that in such case the hammer element 18 must be incline The foremost nail being driven is pressed into the groave 88 by spring means, hereinafter described, which form part of the nail magazine M caused during initial driving of the curved nail themachine in the starting position of said first hammer. Another aperture 82 is provided in registration withthe other end 0f the slot to-allow the nail -l 0 to pass freely there'through when said nail is driven. The forward face of the hamm'er in starting position lies immediately in back of tl i'e'he'ad of the nailto be driven. One leg 16a ('Figy lfl y of i the nail head 1'6 sweeps along the is absorbed by the upper part of 'said groove and that a nail'bein'g driven is thus prevented from buckling, and is directed to'the proper point of entry'into material.

It will also be noted that although the nail turns during driving about a center at or very close to the surface of the material into which it is being driven, due to'the necessity for providing the cogwheels 52, '58, the drive shaft 54 and, therefore, the crank 64 turn about a center spacedsub stantially above the turning center-of th'e' flail. owihg'to the resence of this space I 1 between the two centers and to the fact, that 1 the hammer 18 which is driven about one center 3 must. rotate at-a uniform radius, about'the other, 1 the distance between said hammer andthe cenvter or; thedrive shaft 54 will} constantly 'vary Y 3 during *the driving of a nail. Suchmotion is 1 obtained by allowing the roller- 66 to freely slide i in theslot in thecrankfikgThe hammer I8 is Y grtedt travel in the :de ir pa h. b ind e head of a nail because theshoe' 'I'I rides in the channel I2 which is parallel to said path.

It isimpracticalto drive a nail home in one l blow by moving the first hammer a full' 188 from its starting position (shown in Fig. '10) l due. to thefact that theblock I8 and crank .54 1 would strike the material into -,which a nail-is being drivenbefore-the hammer J8 could itself reach'the material. Therefore, when a nail be- 3 ing driven covers an arcoifsub'stantially or close I to 180, the driving impulse applied by the first hammer will only suffice .to drive the nail part way home and another impulse should befur- V nishedbya second hammerto finish driving the I naiL It' will be realized that if the arc traversed by the first hammer is equal to or greater than 1 the angular length of the curved nailbeing driven then no second hammer needbe employed. However, since it may be desirable to use a curved self-retroverting nail covering an are which is close to 180 ,'I have shown in conjunction with my nail driving machine I8 a second hammer and means for actuating the same.

. The means for driving the second hammer derives power from the sleeve 88 which is turned by the mutilated cog-wheel 58. Said sleeve car:

ries an integral disc 98 (Figs. 7 and 12) disposed 1 intermediate the cogwheel 58 and crank 64. This disc supports a square post 92 which extends radially outward and is capped by a head 93. A bridge 94 is mou'nted on said post. The bridge includes a block portion 85 (Fig. 12) having a medially constricted aperture 98 through which the post 92 passes. The aperture is of such configuration as to permit the block to rock on the postabout an axis ,parallel to the axis of the sleeve 60 and to slide longitudinally of the post. Aspring I88 encircling the post 92 and heldin compression between thehead 93 andthe block 96 biases thebridge 94 toward the center about which the disc 98 turns. r

- The bridge also includes a roller I82 coplanar with the. crank 54 and adapted to ride on the periphery thereof. Another element carried by the bridge is a finger I84 hereinafter referred to as the second hammer/{which is coplanar with the first hammer and is urged by the spring;l88 toward the driving slot 88. Finally, the bridge 94 includes a lug I85 to which a spring 188 is attached. The other end of said spring; is fixed to a s'tationary point on the casing 22-whereby the bridge 94 and second hammer are biased to their starting positions (shown in Fig. 12). Intermediate the second hammer I84 and. roller I82 the bridge hasa hardened arcuateshoe IIII (Fig: 15) which is adapted to cooperatewith a rail I I2 comprising the top surface ofone of the walls of the slot 88 when the second hammer is in drivin position. This rail is a circular segment whose center is coaxial withthe turning center of a nail. r 5

It will be appreciated that whenboth hammers are in starting position (Fig. 12) and a nail Illis in the slot 88 and lodged against groove 88 in the standard. 62 ready to'be driven, the second hammer J84, due to the presence of the nail hammer.

its working stroke (Fig. 14) and'is being retracted by the spring 84, the crank periphery "4 will again raise the bridge 94 permitting said first hammer torepass beneaththe second hammer. When the crank 64 and first hammer 18 are fully retracted, this position being defined by abut:-

ment of the block .18 and machine base 28, the cam-shaped periphery II4 facing the roller I82 is-so close to the drive shaft 54 (Fig. 10) as-to permit the bridge 94 to descend to a level such that the shoe I I8 will rest upon the rail IIZ. In this position the second hammer willbe disposed in the driving slot 88 with its forward face behind the head of a partially driven nail.

The multilated portion of the gear 58 is so arranged that after the first hammer element has completed its driving stroke and the spring 84 been given sufiicient time to fully retract the first hammer, the operative portion of said gear 58 will mesh with the cogwheel 58 starting to drive the second hammer. This cogwheel will be driven V by the unmutilated portion of the gear 58 the. remaining angular distance'necessaryto drive the nail home, the position of, the second hammer being shown in-Fig. 16 at the end of its working stroke. v. w 7 1 It will be noted that due to the configuration of the passageway 98 in the block 9 6, the bridge 94 can rock and slide during the working stroke of the second hammer, this being necessary since the second hammer, like the first hammer, travels during driving ata uniform radius about a center spaced from' the center about which it is driven. Said second hammer is guided in its proper path of travel by the sprin I88 which presses the shoe I I8 against the rail I I2. 7 V

The under-surface of the second hammer I84.is cut away, as at I I5, to such an extent that when the secondfhammer is at the end of its working stroke there will be sufiicient clearance behind it to enable the next nail to be driven to enter intothe driving slot 88 in a manner shortly to be described. The second hammer is returned to starting position, which is defined by abutment of the post 92 and a wall of the casing 22,=subsequent to completion of its working stroke by the spring I88, which will. become effective afterthe v will come to an end, the hammers and actuating means therefor having been. restored to their:

starting positions by the springs 84, I88 there to await initiation of a new cycle when the button 42 is again depressed. r A 1 Thenail magazine M comprises an 'arcuate shell I I6 which extends forward from the standardBZ and on whose surface a supply of curved 1.9; I nails lie. portionpfatheshell adjacent the heads of the: nails is l lefwhich extends into the driving slot 8nvso that nails may freel-y move from the magazine into driving position. The 'm'agazineis covered by'a cap |.2- which 'frictionally engages :the base l 251 andmachine housing-Z21 'I 'he: shell: H6 is provide'dw'ith a longitudinal slot i212 throughwhich the leg 124 of a pusher :plate lzfi freely projects. A spring IZBtensioned between this leg and a stationary point adjacent the standard 62 urges the pusherplate against the rearmost nail in the magazine and at the sametirne stronglypresses the foremost nail being driven against in a sidewall ofethe driving'slot 81!; For convenienoe, the several nails in the magazine prior toinsertionrhay be loosely tacked together as with a light coat of: varnish; lacquer, or-thelike.

provided" with a channel.

the groove,

will be cammed radiallyoutward-lyby [the -Thehousingand cap may be provided with markers likethe arrows I30 to assist in locating;

the point at machine. I V

The machine justdescribed operates in the-followingmanner upon depression of. the button 42 which a-nailwill be driven bythe to drive a curved nail. At the start of an opera tive driving cycle the foremost nail lies in the hole 82. When the one-revolution'clutch is engaged upon depression of the button =42-the mu-- tilated' gear 48' wil1. turn the cogwheel- 52 caus ing thecrank 64 'to revolve and force the hammer 18 along: the path it'is desired to have the nail head travel. While thecrankis turning its pe-" riphery I I4 raises the-bridge 9 4 and second hammer I04 out of the path of travel of the first hammer 18 -:asindicated by-the dot and dash lines in Fig. 14. After the strokeof the first hammer is completed and the mutilated gear 48 and cogwheel 52 disengaged; the first hammer will be:

retracted by the spring 84. During retraction neither cogwheeI 52; 58 is turned although the; shaft Mi continues to rotate. Retraction ofthe first hammer and its associated crank" 64 will permit the bridge 94" to drop into operative positionwith theshoe H 0 againstthe rail land with the second hammer I04 in the slot 80; Immediately this'has occurre'd', the operative-portion of the mutilatedgear 50 will engage th cogwheel' 58 causing the'same hammer to the position in Fig. l6. In this position the'nail will be driven completely home with its head slightly belowthe surface of the material into which it is entering. I

It will be appreciated that while anail is being driven or as long as even a portion-thereof or of either of the hammers 18, I04 remain in the slot 80, the neizt succeeding nail cannot be forced into .said slot by the spring I 28) This is particularly'true since all the nails in'ust-r'emainin parallel relationship due to the factthat they are lightly tacked together'an'd are closely conto driVethe second i fined inthe space between the'shell H6 and'cap I20. However, afterthe foremost nail being driven hashad its head embeddedinto the mate-' rial and-thefirst hammer is inthe position shown in Fig, 10- and the" second hammer=in the -posi.-'. shown in Fig. 16, the driving slot will be tion clearso that the next succeeding nailcan enter therein- Th econd hammer-, pon; retr tip of: said next'succeedi-ng nailand will ride back to its starting position while restin v upon the top of the shank of the nail insaid-sloti c 1 It may be mentioned-thatzthe energy for driv ing; the two hammers is supplied by the flywheel- 28' which necessarilyslows d'ownsomewhat dur'a ing the driving cycle, the.relativefichange irr the. angular speeds of said flywheel and of the-motor shaft 26 being permitted by'theslip. driveiifln Z'It' will thus be seen that thereispriovided a1 device" and {method for using the; same; inwhich the several objects of this inyention are achieved; and which is well adapted to meet the conditions of practical;use. 11:5. :f-

As vari us. possible embodimentsgmight, be made; of the above invention and; as; various changes;

might be made inthe embodimentabove.set-forth, it is to: be understood-that allgmattenhereinrset forth; or shownin the accompanying drawings is to beinterpreted i lu t ativ a d not-inf at mifinssen a Having thus describe my invention}lyclainr as new anddesire to se cure.by- Letters Patent -d, ns too r e on a ed nails aving: i udina curved shanks-which extend-over;

at l a 9 f, a d z q l comnr sinameans. for sum:

portin a c rv d n il andiman zrforrapplyin to he. ea of he ia a-sdr v n i: r e; which: changesits, direction as the nail; is driven in such.

manner that said force is always directedgsukbe t a y per d ular to: the: n il head- .2. A driving tool forelongatednails having:

longitudinally curved shanks,,said ;;tool comprise s; mea s o s ppo tin a. curved; nail; mean for applying to thephe'adiioiatheznaili.agdriving? force gwhichchanges its: direction-as, the, nail is;

drivenin such manner that. said force is always.

directed substantially perpendicular to. the n'aili head, and means for guidingthe nail shanklfor' arcuate movement; as it is driven.

3. A driving 'toolpfor elongated nails having. longitudinally curved shanks, said tool comprise" ing means for: supporting. a curved nail means or ply ng to the headof the hall. a. drivingtforce which changes itsdirection; as the-nail is driven in such mannerthat said .force. is 'always directed: substantially perpendicular to the nail head, self-contained power 5 means for actuating: said force-applying means-and means .for guid-J in githe nail shank forarcuatemovement as itis driven. 7

4; A driving tool for. elongated nails having longitudinally curved; shanks, said tool compris-J ing means'ior supportinga'curved nail, means for applying tothe .head of. the naila driving force which changes its direction as the nailis' driven ina'such manner that said .force is always directed substantially perpendicular to thenail head, a motor for actuating said 'force applyi'ng means, and meansfor guiding the nail shank'for arcuate movement as it is driven.

5. Aqdriving-tool tor elongated nails having longitudinally curved shanks, said tool comprising means for supporting a curved nail, means for, applying to the head" ofthe nail a "driving force which changesits direction as the 'riail" is driven in-such manner that said force is always directed substantiallyperpendicular to the nail? f head, self-containedpower meansfor actuating? 7 said forceapplying means, 'a clutch interm'e'diat said power means and said force applying means; manuallyae'controlled means for operating said he nailshankior" -A":driving tool for elongated nails having longitudinally curved shanks,- said tool compris ing means for supporting a curved nail; means for applying, to the headf'of. the nail a driving force whichxchangesit's direction as the nail-is driven'iinssuch manner that said force is always} directed substantially perpendicular: to the nail head=, self-contained"power means for actuating saidmforcei' applying means; a one-revolution clutch intermediate said'power means and said force applying means, manually controlled means forlengaging said clutch; and means forguiding the'fnailshank for' 'arcuate movement'as it is: driven'f'f 3 i '7; A driving tool for elongated nails-'rhaving longitudinallycurvedshanks, said'tool compris-j ing-means for supporting'a curved nail,'lm'eans for feeding'oneknail at a time to said supporting]; m'e'ans'," an'd 'meansfor applyingto the head of the mu a driving-force which 'changcs its direc-j tion' as'th'e nail is driven in such manner that said force is always directed substantially per-1 'pendicular to thenail head.

8. A' driving tool for elongated nails having;

longitudinally curved shanks, said'tool comprise ing'inean's for supportinga curved nail, a maga zinemeans'for feeding onenail at a time from said magazine to-said supporting means, and

means for applying to the; head of the nail a driving-force which changes its direction as the nailis' driven in such manner that said force is always-directed subst'antially' perpendicular to the nail head. v g

9, IA driving too, *for elongated nails-having longitudinally curved shanks, said tool compris ingia plurality of members which define a curved passageway for supporting and guiding said-nail for: arcuate movement during driving thereof,"

a'ndidriving means for applying a force to the head of the nail being driven through said passageway in such manner that said force is always directed substantiallyperpendicular to the nail head?" 10." A tool asset forthin claim 9 wherein said driving means: comprises a hammer element whichitmoves along a curved path behind'the head of a nail being driven.

{1 1; A tool asset forth in claim 9 wherein-said 'dri'vingmeans comprises apair of hammer ele-jments, each of whichmove along successive portions of a curved pathbehind the head of anail being driven.

for v arcuate movement during: driving thereof; a shaft, means for "rotating said shaft, a slip drive driven by said shaft,-a fly-wheel driven by said slip drive, a hammer 'elementdrivenby said cfly wheel for applying a force to the headof a nail, said element being movable along a curved path,

.15; A tool asi'setfforth in claim 14 wherein a clutch is disposed intermediate said fly-wheel and said hammer element.

16. A tool as set forth in claim 14 whereina one-revolution clutch is interposed between said fiy-wheel and said hammer element andwherein; said clutch is controlled by manually operabletrip 'means. a

17. A driving tool for driving elongatednails having longitudinally curved shanks.aboutacen-- ter substantially coincidentwiththe; surface of i the material into which the nail is being driven,

said tool comprising a hammer element, 'means to guide said element at a uniform radius about, a center coincident with said. nail turningcenten and means to drive said nail about a center spaced A fromsaid turning center.- V

' to guide said element at a-uniform radius about which permitscrelative rocking and-sliding. movei- 'ment thereof." I

' 12.. A tool as set forth in claim 9 wherein said driving means comprises a pair of hammer elements, each of which move along successive portions of acu'rved path behind the head of a nail being driven, and means to move the last acting of said elements out of the path of the first acting of'said elements during-actuation of said first V acting k element.

13; A ,tool' as set forth in claim 9 wherein said driving means comprises a pair of hammer elements, each of which move along successive portions of a curved pathbehind the head of a, nail ;being-driven,'means to movethe last acting of saidelements out of 'the path of the first acting V of said-elements'during actuation ofsaid first acting element, means to retract-saidfirst acting element afteractuation thereof, and means to I ,"p1ace:s aid second acting element :behind the head of ,;the;nail afterisaid first acting element is re-' a 14. A tool for driving elongated nails havin j longitudinally curved shanks, said tool comprising,

, means for supporting and guiding a curved nail a center coincident withsaid nail turning center; and means. to drive said, nail about a center spaced from said turning center, said guide means 7 and said drive means being connected-by means 19.,A driving'tool for elongated 'nailshaving'; longitudinally curved shanks,-said tool, compris a ing means for supporting and guiding a curved nail for arcuate movement during driving'thereof, 1 7 a hammer, means to direct said hammer through an arcuate path of travel substantially coincident withthe path of travel of the nail head;

and means to move said hammer-through said pathin the direction the nail is to be driven,"

whereby to apply a driving force to the head of the'nail throughout the time-it is driven,'which'1 force changes its directionas the nail is driven in such manner as'to always be directed sub-'- stantially perpendicular to thenail headm f 20. ;A driving tool for elongated nails' having longitudinally curved shanks, said-tool compris ing means for'supporting and guiding a curved nail for arcuate movementzduring driving therer of, a hammer, means to direct saidhainmen through anarcuate path of travel substantially coincident with the path of travel of the nail head, means to move said hammer throughsaid I path in the direction the nail is to be driven.

whereby to apply a driving force to thehe'ad 'of the nail throughout thetime it is driven, which force changes its direction as the nail is driven in such manner as to always bedirected substan tially perpendicular to the nail head, a magazine to house a supply of curved nails, and means-"to feed, one nail at a time to saids'upp orting and guiding means.

7215A toolas set forthv inclaim -19 wherein? the hammer is moved through an arc shorten than the arcuate length of the nail, and wherein a second hammer directed and moved in a mam ner similar to the first hammer is provided; to drive the nail for therernainderof i'ts angularf 'length. 7 r

22'.-A driving, tool for elongated nails havingl'l longitudinally curved shanks, said toolcornpris-f 13 ing means for supporting and guiding a curved nail for arcuate movement during driving thereof, a pair of hammers, means to direct one of said hammers through an arcuate path of travel substantially coincident with an initial portion of the path of travel of the nail head, means to direct the other hammer through an arcuate path of travel substantially coincident with the remainder of the path of travel of the nail head,

separate means to move first one and then theother of the hammers through their paths whereby to apply a driving force to the head of the nail throughout the time it is driven, which force changes its direction as the nail is driven in such manner as to always be directed substantially perpendicular to the nail head, said second hammer being locatedin the path of travel as the first hammer, and means to move said second hammer towards and away from such position whereby said first hammer may drive the nail head beyond the second hammer before the second hammer completes driving of the nail.

23. A tool as set forth in claim 22 wherein the means for moving the second hammer out of its position lying in the path of travel of the first hammer is associated with the first hammer.

24. A driving tool for elongatednails having longitudinally curved shanks, said tool comprising a bed, means carried by said bed for'sup: porting and guiding a curved nail for arcuate movement during driving thereof, a hammer, means supported by said bed to direct said hammer through an arcuate path of travel substantially coincident with the path of travel of the nailhead, means to move said hammer through said path in the direction the nail is to be driven, whereby to apply a driving force to the head of the nail throughout the time it is driven, which force changes its direction as the nail is driven in such manner as to always be directed substantially perpendicular to the nail head, and an electric motor also carried by said bed for actuating said hammer moving means.

JOHN N. M. HOWELLS. 

